Image forming apparatuses are used as printers, facsimile machines, copiers, plotters, or multi-functional devices having two or more of the foregoing capabilities. As a conventional type of image forming apparatus, an image forming apparatus is known that feeds a long-size rolled sheet (hereinafter, rolled sheet) in a certain feed direction (hereinafter, sheet feed direction) to form an image on the rolled sheet.
The image forming apparatus typically has a sheet cutting device to cut the rolled sheet to a desired length by moving a cutter in a direction perpendicular to the sheet feed direction (hereinafter, width direction). The cutter used in the sheet cutting device may be, for example, a pair of circular blades to cut sheets of different thicknesses or materials. In particular, recently, such cutters are widely used in inkjet-type image forming apparatuses capable of forming images on sheets of different thicknesses or materials.
Such a conventional sheet cutting device having the cutter formed with the pair of circular blades needs to return a cutter holder holding the cutter to an initial position (home position) in preparation for the next sheet cutting. At this time, if a forward path along which the cutter moves to cut the sheet is identical to a backward path along which the cutter moves to return to the home position, the cutter contacts the already-cut sheet on the backward path, thus hampering movement of the cutter holder (so-called “cut jam”) or causing other failure.
To prevent such a cut jam or other failure, for example, JP-2009-214200-A proposes an image forming apparatus including a sheet cutting device in which the backward path of the cutter formed with the pair of circular blades differs from the forward path of the cutter. Relative to the forward path, the backward path is arranged at a downstream side in the sheet feed direction in which the sheet is fed along a sheet feed path indicated by a broken line P in FIG. 16 and at a position away from a leading edge of a subsequent divided sheet upstream from the cutter in the sheet feed direction. Specifically, after the cutter finishes the cutting operation, the cutter holder is tilted toward the downstream side in the sheet feed direction around a guide member for guiding the movement of the cutter holder. Thus, the position of the cutter moving along the backward path in the sheet feed direction is shifted to the downstream side in the sheet feed direction relative to the position of the cutter moving along the forward path.
Such a configuration can prevent the cutter from contacting the already-cut sheet on the backward path, thus preventing a cut jam. However, in the image forming apparatus described in JP-2009-214200-A, as illustrated in FIG. 16, the cutter holder 510 and the carriage 150 holding the recording head 160 are arranged independently of each other and in tandem in the sheet feed direction indicated by an arrow FD. As a result, the width W0 of the image forming apparatus in the sheet feed direction is relatively large. In addition, because the cutter holder is tilted toward the downstream side in the sheet feed direction, the image forming apparatus requires space for the cutter holder to pivot at the downstream side in the sheet feed direction, thus increasing the width W0 of the image forming apparatus. Thus, the sheet cutting device described in JP-2009-214200-A increases the width of the image forming apparatus and, as a result, increases the size of the image forming apparatus.
As described above, in the image forming apparatus, the forward path of the cutter differs from the backward path, thus preventing the cutter from contacting the cut sheet. However, the cutter holder still remains on the sheet feed path after cutting operation. As a result, a subsequent sheet cannot be fed from the rolled sheet until the cutter and the cutter holder return to the home position, thus hampering gains in productivity.